Effect of approach side during anterior cervical discectomy and fusion on the incidence of recurrent laryngeal nerve injury

Machine learning models for predicting dysphonia following anterior cervical discectomy and fusion: a Swedish Registry Study

BACKGROUND

Dysphonia is one of the more common complications following anterior cervical discectomy and fusion (ACDF). ACDF is the gold standard for treating degenerative cervical spine disorders, and identifying high-risk patients is therefore crucial.

PURPOSE

This study aimed to evaluate different machine learning models to predict persistent dysphonia after ACDF.

STUDY DESIGN

A retrospective review of the nationwide Swedish spine registry (Swespine).

PATIENT SAMPLE

All adults in the Swespine registry who underwent elective ACDF between 2006 and 2020.

OUTCOME MEASURES

The primary outcome was self-reported dysphonia lasting at least 1 month after surgery. Predictive performance was assessed using discrimination and calibration metrics.

METHODS

Patients with missing dysphonia data at the 1-year follow-up were excluded. Data preprocessing involved one-hot encoding categorical variables, scaling continuous variables, and imputing missing values. Four machine learning models (logistic regression, random forest (RF), gradient boosting, K-nearest neighbor) were employed. The models were trained and tested using an 80:20 data split and 5-fold cross-validation, with performance metrics guiding the selection of the best model for predicting persistent dysphonia.

RESULTS

In total, 2,708 were included in the study. Twelve key predictors were identified. Four machine learning models were tested, with the RF model achieving the best performance (AUC=0.794). The most significant predictors across models included preoperative NDI, EQ5Dindex, preoperative neurology, number of operated levels, and use of a fusion cage. The RF model, chosen for its superior performance, showed high sensitivity and consistent accuracy, but a low specificity and positive predictive value.

CONCLUSIONS

In this study, machine learning models were employed to identify predictors of persistent dysphonia following ACDF. Among the models tested, the RF classifier demonstrated superior performance, with an AUC value of 0.790. The RF model identified NDI, EQ5Dindex, and number of fused vertebrae as key variables. These findings underscore the potential of machine learning models in identifying patients at increased risk for dysphonia persisting for more than 1 month after surgery.

Atrophy of the Posterior Cricoarytenoid Muscle as an Indicator of a Recurrent Laryngeal Nerve Injury History Before Revision Anterior Cervical Spine Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVES

In our recent study, we observed some cases of symptomatic normal vocal cord motility instead of asymptomatic vocal cord palsy (VCP) in preoperative laryngoscopy of a revision anterior cervical spine surgery (ACSS) cohort. We assumed the intrinsic muscle atrophy caused by recurrent laryngeal nerve injury could cause vocal cord-related symptoms. Thus, radiological examinations were reviewed in relation to the posterior cricoarytenoid (PCA) muscle, one of the intrinsic muscles.

METHODS

We retrospectively analyzed 64 patients who underwent a revision ACSS. Patients with vocal cord-related symptoms were classified as symptomatic group (group S, n = 11), and those without symptoms as asymptomatic group (group AS, n = 53). The bilateral size and signal intensity of the PCA muscles in these patients were measured in the axial view with preoperative computed tomography (CT) and magnetic resonance imaging (MRI) evaluations. Since the size and signal intensity values were different on each image, the ratios of the contralateral and ipsilateral muscle values were analyzed for each modality.

RESULTS

There was no VCP on laryngoscopy study. However, the mean ratio of the PCA muscle size on CT was 1.40 ± .37 in group S and 1.02 ± .12 in group AS (P = .007). These values on the MRI were 1.49 ± .45 in group S and 1.02 ± .14 in group AS, which was also a significant difference (P = .008).

CONCLUSIONS

Evaluating the size of the PCA muscle before revision ACSS may predict a previous recurrent laryngeal nerve injury. Careful planning for the appropriate approach should be undertaken if vocal cord-related symptoms and atrophy of PCA muscle are evident.

Recurrent Laryngeal Nerve Injury During Anterior Cervical Discectomy and Fusion (ACDF): A Case Presentation and Review of the Literature

Anterior cervical discectomy and fusion (ACDF) is a surgical procedure used to manage spine pathology including disc herniation, spondylosis, and myelopathy. During the operation, the vertebral segment of interest is accessed via the anterior neck and the disc space is fully resected along with osteophytes to relieve the compression along the affected nerve. While the procedure is regarded as being highly effective in improving symptoms, there are several complications associated with the surgery that patients should be cautioned about. We present a case of a patient with oropharyngeal and cervical esophageal dysphagia and left vocal cord paralysis following a C5/C6, C6/C7, and C7/T1 ACDF for multilevel cervical stenosis and disc herniation. Otolaryngology evaluation confirmed vocal cord paralysis from recurrent laryngeal nerve palsy (RLNP) and the patient's symptoms were managed with a vocal cord injection and speech therapy. This report explores the surgical approach for ACDF along with its complications and postoperative care.

Postoperative Measurement of the Retropharyngeal Space Predicts the Risk of Dysphagia After Anterior Cervical Diskectomy and Fusion

BACKGROUND AND OBJECTIVES

Postoperative dysphagia is a common complication of anterior cervical diskectomy and fusion (ACDF), although its pathophysiology remains poorly understood. Patients with severe dysphagia may suffer from serious complications such as aspiration pneumonia, in addition to difficulty with oral intake or malnutrition; therefore, a prompt indicator for postoperative management would be helpful. We quantitatively evaluated the retropharyngeal space (RS) after ACDF and investigated its association with postoperative dysphagia.

METHODS

This multicenter retrospective study analyzed the clinical data of 82 consecutive patients who underwent ACDF. The anteroposterior distance (APD) of the RS was measured at the C2 level using a lateral radiographic view on postoperative day 1. Postoperative dysphagia was subjectively assessed using the Bazaz-Yoo Dysphagia Severity Scale. We statistically evaluated the association between the APD of the RS and postoperative dysphagia.

RESULTS

The mean APD of the RS in all 82 patients was 3.6 mm preoperatively and significantly increased to 8.2 mm postoperatively (P < .0001). Twenty-two patients (26.8%) had postoperative dysphagia. Multivariable analysis revealed that the postoperative APD was associated with postoperative dysphagia (odds ratio 1.27, 95% CI 1.10-1.50, P = .0007). The receiver operating characteristic curve (area under the curve 0.70, 95% CI 0.58-0.83) demonstrated that the postoperative APD of the RS cutoff value was 6.1 mm, with a sensitivity of 100% and a specificity of 35%. With this cutoff value, the positive and negative predictive values for postoperative dysphagia were 36% and 100%, respectively.

CONCLUSION

Our data demonstrate that a value of 6.1 mm for the APD of the RS is an effective indicator for dysphagia after ACDF, which contributes to optimizing the patient management in the acute postoperative period.

Effect of Fusion and Arthroplasty for Cervical Degenerative Disc Disease in Active Duty Service Members Performed at an Overseas Military Treatment Facility: A 2-Year Retrospective Analysis

INTRODUCTION

Among U.S. military active duty service members, cervicalgia, cervical radiculopathy, and myelopathy are common causes of disability, effecting job performance and readiness, often leading to medical separation from the military. Among surgical therapies, anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are options in select cases; however, elective surgeries performed while serving overseas (OCONUS) have not been studied.

MATERIALS AND METHODS

A retrospective analysis of a prospectively collected surgical database from an OCONUS military treatment facility over a 2-year period (2019-2021) was queried. Patient and procedural data were collected to include ACDF or CDA surgery, military rank, age, tobacco use, pre- and post-operative visual analogue scales for pain, and presence of radiographic fusion after surgery for ACDF patients or heterotopic ossification for CDA patients. Chi-square and Student t-test analyses were performed to identify variables associated with return to full duty.

RESULTS

A total of 47 patients (25 ACDF and 22 CDA) underwent surgery with an average follow-up of 192.1 days (range 7-819 days). Forty-one (87.2%) patients were able to return to duty without restrictions; 10.6% of patients remained on partial or limited duty at latest follow-up and one patient was medically separated from the surgical cohort. There was one complication and one patient required tour curtailment from overseas duty for ongoing symptoms.

CONCLUSIONS

Both ACDF and CDA are effective and safe surgical procedures for active duty patients with cervicalgia, cervical radiculopathy, and cervical myelopathy. They can be performed OCONUS with minimal interruption to the patient, their family, and the military unit, while helping to maintain surgical readiness for the surgeon and the military treatment facility.

Anterior Cervical Corpectomy and Fusion for Degenerative Cervical Spondylotic Myelopathy: Case Presentation With Surgical Technique Demonstration and Review of Literature

Anterior cervical corpectomy and fusion (ACCF) provides an extensive decompression and provides a large surface area for fusion in patients presenting with cervical spondylotic myelopathy. Unfortunately, this procedure is a more difficult spinal surgery to perform (compared with a traditional anterior cervical discectomy and fusion) and has a higher incidence of overall complications. In literature, ACCF has functional outcomes that seem clinically equivalent to those for multilevel anterior cervical discectomy and fusion, especially when contained to 1 vertebral body level, and in cases, for which both posterior and anterior procedures would be appropriate surgical options, may provide greater long-term clinical benefit than posterior fusion or laminoplasty. In this manuscript, we summarize the indications and outcomes following ACCF for degenerative cervical spondylotic myelopathy. We then describe a case presentation and associated surgical technique with a discussion of complication avoidance with this procedure.

A Tapered Cuff Tracheal Tube Decreases the Need for Cuff Pressure Adjustment After Surgical Retraction During Anterior Cervical Spine Surgery: A Randomized Controlled, Double-Blind Trial

Background

Surgical retraction to expose the vertebrae during anterior cervical spine surgery increases tracheal tube cuff pressure and may worsen postoperative sore throat and dysphonia. This randomized double-blind study investigated the effect of cuff shape on intraoperative cuff pressure and postoperative sore throat and dysphonia.

Methods

Eighty patients were randomized to tracheal intubation with a tapered cuff or a conventional cylindrical high-volume low-pressure cuff (control) during anesthesia. Intraoperative cuff pressures were compared. The primary outcome was the incidence of pressure adjustment needed when the cuff pressure increased to &gt; 25 mm Hg after surgical retraction. The secondary outcome was the incidence of postoperative sore throat and dysphonia.

Results

The incidence of pressure adjustment after surgical retraction was significantly lower in the tapered group than in the control group (13% vs. 48%; P = 0.001; relative risk reduction, 74%). The median [interquartile range (IQR)] cuff pressure (mm Hg) was significantly lower for the tapered cuff than for the control cuff before surgical retraction [9 (7–12) vs. 12 (10–15); P &lt; 0.001] and after retraction [18 (15–23) vs. 25 (18–31); P = 0.007]. The median (IQR) postoperative dysphonia score assessed by a single speech-language pathologist was lower in the tapered group than in the control group [4 (3–6) vs. 5.5 (5–7); P = 0.008].

Conclusion

A tapered cuff tracheal tube decreased the need for the adjustment of cuff pressure after surgical retraction during anterior cervical spine surgery, thereby avoiding intraoperative pressure increase. It also has a better outcome in terms of dysphonia.

Clinical Trial Registration

[www.clinicaltrials.gov], identifier [NCT04591769].

Laryngoscopic Screening Before Revision Anterior Cervical Spine Surgery: Is Vocal Cord Palsy a Relevant Factor in Deciding the Approach Direction?

STUDY DESIGN

Retrospective study.

OBJECTIVES

The aim was to evaluate the exact incidence of vocal cord palsy (VCP) caused by previous anterior cervical spine surgery (ACSS) and aid surgeons in deciding the approach direction in revision ACSS.

SUMMARY OF BACKGROUND DATA

The incidence of VCP detected by preoperative laryngoscopic screening before revision ACSS appeared to be much higher in previous reports than in our experience.

MATERIALS AND METHODS

We reviewed the data of 64 patients who underwent revision ACSS. Preoperative laryngoscopy was performed in all patients to detect VCP and/or structural abnormalities of the vocal cords. The patients' characteristics, laryngoscopy results, and symptoms before revision surgery that were potentially caused by previous recurrent laryngeal nerve injuries (voice change, foreign body sensation, and chronic aspiration) were recorded.

RESULTS

Laryngoscopy demonstrated no complete VCP or decreased vocal cord motility. Eleven patients (17.2%) showed vocal cord-related symptoms and 13 patients (20.3%) showed abnormal laryngoscopic findings without VCP. Four patients (6.2%) showed vocal cord-related symptoms and abnormal laryngoscopic findings simultaneously. At the initial operative level, no significant differences in vocal cord-related symptoms were observed between the upper and lower levels (C3-4-5 vs. C5-6-7). However, the frequency of vocal cord-related symptoms was significantly high at the larger number of levels (≥3 segments) (P=0.010).

CONCLUSIONS

In contrast to previous reports, this study demonstrated that VCP is rarely detected before revision ACSS. Therefore, deciding the approach direction with only vocal cord motility can be dangerous, and more attention is required in setting the approach direction in patients who show both vocal cord-related symptoms and abnormal laryngoscopic finding. In other cases, a contralateral approach which has a low risk of bilateral VCP could be utilized if necessary.

Characterization of dysphagia following anterior cervical spine surgery

BACKGROUND

Post-operative dysphagia is one of the most common complications of anterior cervical spine surgery (ACSS).

OBJECTIVE

Examine post-operative structural and physiologic swallowing changes in patients with dysphagia following ACSS as compared with healthy age and gender matched controls.

METHODS

Videofluoroscopic swallow studies of adults with dysphagia after ACSS were retrospectively reviewed. Seventy-five patients were divided into early (≤2 months) and late (> 2 months) post-surgical groups. Modified Barium Swallow Impairment Profile (MBSImP), Penetration-Aspiration Scale (PAS) scores, and pharyngeal wall thickness (PWT) metrics were compared.

RESULTS

Significant differences were identified for all parameters between the control and early post-operative group. MBSImP Pharyngeal Total (PT) scores were greater in the early group (Interquartile Range (IQR) = 9-14, median = 12) versus controls (4-7, 5, P < 0.001) and late group (0.75-7.25, 2, P < 0.001). The early group had significantly higher maximum PAS scores (IQR = 3-8, median = 7) than both the control group (1-2, 1, P < 0.001) and late post-operative group (1-1.25, 1, P < 0.001). PWT was significantly greater in the early (IQR = 11.12-17.33 mm, median = 14.32 mm) and late groups (5.31-13.01, 9.15 mm) than controls (3.81-5.41, 4.68 mm, P < 0.001).

CONCLUSION

Dysphagic complaints can persist more than two months following ACSS, but often do not correlate with validated physiologic swallowing dysfunction on VFSS. Future studies should focus on applications of newer technology to elucidate relevant deficits.

Anterior Approach to the Subaxial Cervical Spine: Pearls and Pitfalls

Since its introduction by Smith and Robinson, the anterior approach to the subaxial cervical spine has become one of the standard procedures for numerous cervical spine pathologies, including, but not limited to degenerative disease, trauma, tumor, deformity, and instability. Along with its increasing popularity and improvements in anterior instrumentation techniques, a comprehensive knowledge of the surgical anatomy during the anterior exposure is critical for trainees and experienced spine surgeons alike to minimize the infrequent but potentially devastating risks associated with this approach. Understanding the anatomy and techniques to minimize damage to relevant structures can reduce the risks of developing notable postoperative complications and morbidity.

Neurophysiological monitoring during anterior cervical discectomy and fusion for ossification of the posterior longitudinal ligament

OBJECTIVE

This study aimed to investigate the value of intraoperative neurophysiological monitoring (IONM) in anterior cervical spine discectomy with fusion (ACDF) for ossification of the posterior longitudinal ligament (OPLL).

METHODS

Patients who underwent multimodal IONM (transcranial electrical motor-evoked potentials [tcMEP], somatosensory-evoked potentials, and continuous electromyography) for ACDF from 2009 to 2019 were compared to historical controls from 2003 to 2009. The rates of postoperative neurological deficits, neurophysiological warnings, and their characteristics were analyzed.

RESULTS

Among 196 patients, postoperative neurological deficit rates were 3.79% and 14.06% in the IONM and historical control (non-IONM) groups, respectively (p < 0.05). The use of IONM (OR: 0.139, p = 0.003) and presence of myelopathy (OR: 8.240, p = 0.013) were associated with postoperative neurological complications on multivariate regression. In total, 23 warnings were observed during IONM (17 tcMEP and/or electromyography; six electromyography). Sensitivity and specificity of IONM warnings for detecting neurological complications were 84.2% and 93.7%, respectively.

CONCLUSIONS

IONM, especially multimodal IONM, may be a useful tool to detect neurological damage in ACDF for high-risk conditions such as OPLL with pre-existing myelopathy.

SIGNIFICANCE

The utility of IONM in ACDF for OPLL has not been evaluated due to its rarity. This study supports the use of IONM in cervical OPLL with myelopathy.

Anatomical Variations of the Recurrent Laryngeal Nerve and Implications for Injury Prevention during Surgical Procedures of the Neck

Accurate knowledge of anatomical variations of the recurrent laryngeal nerve (RLN) provides information to prevent inadvertent intraoperative injury and ultimately guide best clinical and surgical practices. The present study aims to assess the potential anatomical variability of RLN pertaining to its course, branching pattern, and relationship to the inferior thyroid artery, which makes it vulnerable during surgical procedures of the neck. Fifty-five formalin-fixed cadavers were carefully dissected and examined, with the course of the RLN carefully evaluated and documented bilaterally. Our findings indicate that extra-laryngeal branches coming off the RLN on both the right and left side innervate the esophagus, trachea, and mainly intrinsic laryngeal muscles. On the right side, 89.1% of the cadavers demonstrated 2–5 extra-laryngeal branches. On the left, 74.6% of the cadavers demonstrated 2–3 extra-laryngeal branches. In relation to the inferior thyroid artery (ITA), 67.9% of right RLNs were located anteriorly, while 32.1% were located posteriorly. On the other hand, 32.1% of left RLNs were anterior to the ITA, while 67.9% were related posteriorly. On both sides, 3–5% of RLN crossed in between the branches of the ITA. Anatomical consideration of the variations in the course, branching pattern, and relationship of the RLNs is essential to minimize complications associated with surgical procedures of the neck, especially thyroidectomy and anterior cervical discectomy and fusion (ACDF) surgery. The information gained in this study emphasizes the need to preferentially utilize left-sided approaches for ACDF surgery whenever possible.

Recurrent laryngeal nerve injury following single- and multiple-level anterior cervical discectomy and fusion: a meta-analysis

Background

Recurrent laryngeal nerve (RLN) palsy is a common and potentially debilitating complication of anterior cervical discectomy and fusion (ACDF). The relationship between the risk of RLN palsy and the number of operated levels remains unclear, and no previous studies address potential differences between short- and long-term RLN injury following ACDF.

Methods

Electronic searches of PubMed, Cochrane, ScienceDirect and Google Scholar were performed from database inception to June 2019. Relevant studies reporting the rate of RLN palsy for patients undergoing ACDF for cervical spine pathology were identified according to predetermined inclusion and exclusion criteria. Statistical analysis was performed using fixed effects and random effects modelling. I2 and Q statistics were used to explore heterogeneity.

Results

Five studies with a total of 3,514 patients were included in the meta-analysis. The incidence of RLN palsy was found to be 1.2%. There were no statistically significant differences in the rate of RLN palsy between multiple- and single-level ACDF [odds ratio (OR) 1.04; 95% CI: 0.56-1.95; P=0.891, I2=0%]. There were similarly no statistically significant differences in RLN palsy rates for multiple- and single-level ACDF when patients were stratified based on length of follow-up of less than or greater than 12 months.

Conclusions

This analysis suggests that there is no statistically significant association between the number of ACDF operative levels and the risk of short- or long-term RLN palsy.

Recurrent Laryngeal Nerve Palsy after Anterior Cervical Discectomy and Fusion - Prevalence and Risk Factors

BACKGROUND AND STUDY AIMS

 Recurrent laryngeal nerve palsy (RLNP) is a potential complication of anterior discectomy and fusion (ACDF). There still is substantial disagreement on the actual prevalence of RLNP after ACDF as well as on risk factors for postoperative RLNP. The aim of this study was to describe the prevalence of postoperative RLNP in a cohort of consecutive cases of ACDF and to examine potential risk factors.

MATERIALS AND METHODS

 This retrospective study included patients who underwent ACDF between 2005 and 2019 at a single neurosurgical center. As part of clinical routine, RLNP was examined prior to and after surgery by independent otorhinolaryngologists using endoscopic laryngoscopy. As potential risk factors for postoperative RLNP, we examined patient's age, sex, body mass index, multilevel surgery, and the duration of surgery.

RESULTS

 214 consecutive cases were included. The prevalence of preoperative RLNP was 1.4% (3/214) and the prevalence of postoperative RLNP was 9% (19/211). The number of operated levels was 1 in 73.5% (155/211), 2 in 24.2% (51/211), and 3 or more in 2.4% (5/211) of cases. Of all cases, 4.7% (10/211) were repeat surgeries. There was no difference in the prevalence of RLNP between the primary surgery group (9.0%, 18/183) versus the repeat surgery group (10.0%, 1/10; p = 0.91). Also, there was no difference in any characteristics between subjects with postoperative RLNP compared with those without postoperative RLNP. We found no association between postoperative RLNP and patient's age, sex, body mass index, duration of surgery, or number of levels (odds ratios between 0.24 and 1.05; p values between 0.20 and 0.97).

CONCLUSIONS

 In our cohort, the prevalence of postoperative RLNP after ACDF was 9.0%. The fact that none of the examined variables was associated with the occurrence of RLNP supports the view that postoperative RLNP may depend more on direct mechanical manipulation during surgery than on specific patient or surgical characteristics.

Analysis of postoperative dysphagia after anterior cervical decompression and fusion

Purpose: To investigate the incidence and risk factors of postoperative dysphagia after anterior cervical decompression and fusion (ACDF) in terms of demographic, procedural and anaesthetic perspectives.Materials and methods: Medical records and radiologic data of patients who underwent anterior cervical surgery performed by two surgeons in a single centre between January 2012 and December 2015 were retrospectively analysed. Patients with spinal tumours, infective spondylitis and traumatic cervical pathologies were excluded. Patients with preoperative dysphagia and previous history of anterior cervical surgery were also excluded. Finally, 127 patients were enrolled. Bazaz dysphagia score was used for the diagnosis of postoperative dysphagia.Results: The incidence of postoperative dysphagia was 10.2% at six weeks after ACDF. Nine patients showed mild dysphagia that fully recovered at three months after ACDF. Four patients showed moderate dysphagia that also recovered fully at six months after surgery. The incidence of postoperative dysphagia increased significantly in cases of C4 or C5 level involvements. Age, sex, hypertension, body mass index, postoperative soft tissue swelling, intubation difficulty and intubation tools were not significant risk factors of ACDF. Diabetes mellitus, two surgical levels, the use of plate, long anaesthetic and operative time and large intubation tube size were causative factors of postoperative dysphagia in multivariable analysis (p < 0.05).Conclusions: The incidence of postoperative dysphagia after ACDF was relatively low, and the prognosis was good.

Total subaxial reconstruction

Cervical deformity, particularly kyphosis, is frequently encountered in surgical practice. While many cases are asymptomatic, some patients may have significant pain and disability. We provide a brief review of the pathophysiology of cervical deformity and the technical aspects of deformity correction in the cervical spine. Anterior techniques reviewed here include anterior cervical discectomy and fusion (ACDF), anterior corpectomy and fusion (ACCF) and anterior osteotomy (ATO). Posterior techniques include laminectomy and fusion, posterior column osteotomy (PCO) and pedicle subtraction osteotomy (PSO). This is a fast-evolving field as our understanding of cervical deformity matures and longer-term surgical outcomes are available.

Right- Versus Left-sided Exposures of the Recurrent Laryngeal Nerve and Considerations of Cervical Spinal Surgical Corridor: A Fresh-Cadaveric Surgical Anatomy of RLN Pertinent to Spine

STUDY DESIGN

Cadaveric study on fresh unprocessed, nonpreserved, undyed specimens which have not previously been reported.

OBJECTIVE

We aimed to perform surgically relevant exposures of the anterior cervical spine with particular attention to observing the potential vulnerabilities of the RLN on right and left.

SUMMARY OF BACKGROUND DATA

Vulnerability of the RLN in the anterior cervical spine approach on the right versus left is the subject of ongoing debate. Although most cadaveric studies focus on course variations, structural relations of RLN, they have been done in preserved (fixed) cadavers without relevance to the needs of spinal exposure.

METHODS

Twelve fresh undyed cadavers had extensive layer by layer dissections by 2 surgeons (one with extensive experience as anatomy dissector). Both sides were explored for vulnerability during cervical spinal procedures. Each dissection was carried out in a phased approach and deliberately explored beyond what can be afforded in live surgery to allow the reader to conceptualize a better view of the structures.

RESULTS

In all specimens, we consistently demonstrated that the right surgical corridor involved manipulation of the nerve and its branches especially below C5 to achieve optimum midline access: in the right corridor, the RLN is on its oblique course to the tracheoesophageal groove. On the left, RLN is already in the tracheoesophageal groove and out of the surgical field involving minimal direct mobilization of the nerve.

CONCLUSION

RLN surgical anatomy photographed here is novel in using fresh unprocessed cadaveric specimens which has previously not been reported.Right surgical corridor, below C5, involves retraction/manipulation of RLN for achieving optimum spinal midline access, highlighting potential surgical vulnerability of right RLN.

LEVEL OF EVIDENCE

3.

Right Versus Left Approach to Anterior Cervical Discectomy and Fusion: An Anatomic Versus Historic Debate

The debate over the influence approach sidedness has on the risk of recurrent laryngeal nerve palsy (RLNP) following anterior cervical discectomy and fusion (ACDF) has its origins with the introduction of the procedure for radicular pain in the 1950s. The recurrent laryngeal nerves follow disparate courses in the lower neck secondary to differences in embryogenesis. Because of these differences, some authors believe a right-sided approach increases the risk of RLNP. However, modern surgical series have not shown a clear risk of RLNP with a right- versus left-sided approach. By looking at the historical context surrounding the introduction of ACDF, we propose the dogmatic view of an increased risk of RLNP with a right-sided approach likely arose from a combination of theoretical anatomic risk and the early surgical experience of a pioneer of the procedure.

Platysma sparing approach to anterior cervical spine surgery: A less exposure surgery technique

Introduction

Authors aim to demonstrate the surgical technique and outcomes of using a platysma sparing approach to anterior cervical spine surgery.

Methods

Medical records of 496 prospective patients, group 1 (259 patients) with an outpatient platysma muscle-sparing approach. Group 2 (237 patients) with inpatient standard muscle-splitting approach.

Results

Intergroup comparison showed statistical significant improvement in VAS neck and NDI scores p = 0.009 and p = 0.012 and surgical operative time and estimated blood loss, p = 0.003 and p = 0.006 respectively.

Conclusion

This anatomy sparing technique demonstrates a safe, effective and reproducible approach to cervical spine surgery which is a goal of less exposure surgery philosophy.

Horner Syndrome After Anterior Cervical Discectomy and Fusion: Case Series and Systematic Review

BACKGROUND

Horner syndrome is an infrequently seen complication of anterior cervical discectomy and fusion (ACDF). Multicenter studies have reported a very low incidence, less than 0.1%.

OBJECTIVE

To identify the incidence in, characteristics of, and postoperative course in patients in whom postoperative Horner syndrome developed after ACDF.

METHODS

We performed a retrospective review of all patients who experienced Horner syndrome after ACDF for cervical degenerative disease at a single tertiary care institution between 2017 and 2018. A systematic review was then performed to identify studies investigating prevalence, diagnosis, and treatment of postoperative Horner syndrome after ACDF.

RESULTS

Of 1116 patients at our institution who underwent ACDF, the incidence of Horner syndrome was 0.45%. C4/5 and C5/6 were the 2 most common surgical levels. The complication was noted to occur immediately after surgery, and at least partial improvement was identified in all patients an average 3.5 months after surgery (range, 10 days to 6 months). These findings were consistent with our systematic review of 21 studies that showed an incidence of 0.6% (range, 0.02% to 4.0%), the most common surgical level C5/6 (64%), and 82% of patients experiencing at least partial resolution of symptoms within 1 year (60.7% complete, 21.4% partial resolution).

CONCLUSION

Horner syndrome occurs in 0.6% of patients undergoing ACDF. Careful postoperative examination should reveal this complication, which may be underdiagnosed or underreported in larger multicenter case series. The majority of patients experience complete resolution of symptoms within 6 months to 1 year and can be treated conservatively and expectantly.

Quantitative Risk Factor Analysis of Postoperative Dysphagia After Anterior Cervical Discectomy and Fusion (ACDF) Using the Eating Assessment Tool-10 (EAT-10)

STUDY DESIGN

A retrospective case series.

OBJECTIVE

The aim of this study was to utilize the Eating Assessment Tool-10 (EAT-10) to quantitatively analyze risk factors contributing to dysphagia after anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

ACDF is one of the most common procedures performed in the United States, with postoperative dysphagia rates ranging from 2% to 60%. The EAT-10 is a self-administered, symptom-specific 10-item clinical instrument to document dysphagia symptom severity and has demonstrated excellent internal consistency, test-retest reliability, and criterion-based validity.

METHODS

This study utilized a retrospective chart review of 163 patients from July 2013 to October 2017 who underwent ACDF at a single institution and prospectively completed EAT-10 surveys pre- and postoperatively. EAT-10 scores were collected preoperatively and at postoperative day 1, day 14, 1 month, 3 months, 6 months, and 12 months. Preselected risk factors were abstracted from the patients' chart. Univariate analyses were performed to identify candidate variables that correlated with abnormal EAT-10 scores at each time point. Multivariate logistic regression was then utilized to identify risk factors that were independently correlated with abnormal EAT-10 scores at each time point.

RESULTS

Female gender, younger patients, and increased operating room (OR) time was associated with increased rates of dysphagia in the early postoperative period. History of obstructive sleep apnea, history of asthma, increased American Society of Anesthesiologists (ASA) score, and a larger number of spinal levels included in the surgery were correlated with increased dysphagia in the later postoperative periods.

CONCLUSION

Dysphagia is common following ACDF. Factors associated with longer-term dysphagia seem to be more associated with pre-existing medical comorbidities. Understanding risk factors that correlate with increased rates of dysphagia has the potential to improve preoperative patient counseling and changes in operative management.

LEVEL OF EVIDENCE

4.

Option for transverse midline incision and other factors that determine patient's decision to have cervical spine surgery

BACKGROUND

Authors aim to determine patients' preference for surgical incision and factors affecting the decision for surgery to the anterior neck.

METHODS

A questionnaire was presented prior to evaluation and if preceded to surgery followup given.

RESULTS

243 patients completed questionnaire, with 60% female population and younger than 50 years. 151 patients preferred a transverse midline incision with a statistically significant increase in outcomes and cosmesis importance and a decrease in the importance of board certification.

CONCLUSION

Findings of questionnaire demonstrate that patients' prefer a transverse midline anterior neck incision, with surgical outcomes being the overall factor affecting decision making.

Indications for Direct Laryngoscopic Examination of Vocal Cord Function Prior to Anterior Cervical Surgery

Recurrent laryngeal nerve palsy (RLNP) is among the most common complications in both thyroid surgeries and anterior approaches to the cervical spine, having both a diverse etiology and presentation. Most bilateral paresis, with subsequent devastating impact on patients, are due to failure to recognize unilateral recurrent laryngeal nerve paralysis and, although rare, are entirely preventable with appropriate history and screening. Recurrent laryngeal nerve palsy has been shown to present asymptomatically in as high as 32% of cases, which yields limitations on exclusively screening with physical examination. Based on the available literature, diagnosis of unilateral RLNP is the critical factor in preventing the occurrence of bilateral RLNP as the surgeon may elect to operate on the injured side to prevent bilateral paresis. Analysis of incidence rates shows postoperative development of unilateral RLNP is 13.1 (95% confidence interval [CI]: 6.1-28.1) and 13.90 (95% CI: 6.6-29.3) times more likely in anterior spine and thyroid surgery, respectively, in comparison with intubation. Currently, there is no consensus on when to order a preoperative laryngoscopic examination prior to anterior cervical spine surgery. The importance of patient history should be emphasized, as it is the basis for indications of preoperative laryngoscopy. Efforts to minimize postoperative complications must be made, especially when considering the rising rate of cervical fusion. This study presents a systematic review of the literature defining key causes of RLNP, with a probability-based protocol to indicate direct laryngoscopy prior to anterior cervical surgery as a screening tool in the prevention of bilateral RLNP.

C2-C3 Anterior Cervical Fusion: Technical Report

STUDY DESIGN

Retrospective review of patients at a university hospital.

OBJECTIVE

To describe the anterior approach for cervical discectomy and fusion (ACDF) at C2-C3 level and evaluate its suitability for treatment of instability and degenerative disease in this region.

SUMMARY OF BACKGROUND DATA

The anterior approach is commonly used for ACDF in the lower cervical spine but is used less often in the high cervical spine.

METHODS

We retrospectively reviewed a database of consecutive cervical spine surgeries performed at our institution to identify patients who underwent ACDF at the C2-C3 level during a 10-year period. Demographic data, clinical indications, surgical technique, complications, and immediate results were evaluated.

RESULTS

Of the 11 patients (7 female, 4 male; mean age 46 y) identified, 7 were treated for traumatic fractures and 4 for degenerative disk disease. Three patients treated for myelopathy showed improvement in mean Nurick grade from 3.6 to 1.3. Pain was significantly improved in all patients who had preoperative pain. Solid bony fusion was achieved in 5 of 7 patients at 3-month follow-up. Complications included dysphagia in 4 patients (which resolved in 3), aspiration pneumonia, mild persistent dysphonia, and construct failure at C2 requiring posterior fusion. One patient died of a pulmonary embolism 2 weeks postoperatively.

CONCLUSIONS

ACDF at the C2-C3 level is an option for the treatment of high cervical disease or trauma but is associated with a higher rate of approach-related morbidity. Familiarity with local anatomy may help to reduce complications. ACDF at C2-C3 appears to have a fusion rate similar to ACDF performed at other levels.

Complications of Anterior and Posterior Cervical Spine Surgery

Cervical spine surgery performed for the correct indications yields good results. However, surgeons need to be mindful of the many possible pitfalls. Complications may occur starting from the anaesthestic procedure and patient positioning to dura exposure and instrumentation. This review examines specific complications related to anterior and posterior cervical spine surgery, discusses their causes and considers methods to prevent or treat them. In general, avoiding complications is best achieved with meticulous preoperative analysis of the pathology, good patient selection for a specific procedure and careful execution of the surgery. Cervical spine surgery is usually effective in treating most pathologies and only a reasonable complication rate exists.

A Tunneled Subcricoid Approach for Anterior Cervical Spine Reoperation: Technical and Safety Results

OBJECTIVE

Anterior cervical spine decompression and fusion are common neurosurgical operations. Reoperation of the anterior cervical spine is associated with increased morbidity. The authors describe a novel subcricoid approach to protect the recurrent laryngeal nerve in a cuff of tissue while facilitating surgical access to the anterior cervical spine.

METHODS

Single institution, consecutive case review of 48 patients undergoing reoperation in the anterior cervical region including the level of C5 and below. Univariable and multivariable regression analysis was used to determine predictors of postoperative morbidity.

RESULTS

No intraoperative complications were reported. Estimated blood loss for the approach was 13.6 ± 3.1 mL. Nine of 48 patients developed immediate postoperative complications, including vocal cord paresis (10.4%), moderate-to-severe dysphagia (10.4%), and neck edema requiring intubation (2.1%). No postoperative hematomas or death occurred. All complications occurred with 4 or more levels of exposure (1-3 disc levels, 0%, vs. ≥ 4 disc levels, 31%). Extension of the exposure to the upper thoracic spine was associated with odds for postoperative complications (adjusted odds ratio, 6.50; 95% confidence interval, 1.14-37.03) and prolonged hospital stay (adjusted increase 4.23 days, P < 0.01).

CONCLUSION

The tunneled subcricoid approach is a relatively safe corridor to reapproach the anterior cervical spine at the level of C5 and below. However, caution must be exercised when using this approach to expose 4 or more disc levels and with extension of the exposure to the upper thoracic spine. Future comparative studies are needed to establish patient selection criteria in determining the use of this technique compared with classic approaches.

Anterior Cervical Spine Surgery for Degenerative Disease: A Review

Anterior cervical spine surgery is an established surgical intervention for cervical degenerative disease and high success rate with excellent long-term outcomes have been reported. However, indications of surgical procedures for certain conditions are still controversial and severe complications to cause neurological dysfunction or deaths may occur. This review is focused mainly on five widely performed procedures by anterior approach for cervical degenerative disease; anterior cervical discectomy, anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical foraminotomy, and arthroplasty. Indications, procedures, outcomes, and complications of these surgeries are discussed.

Outpatient Cervical and Lumbar Spine Surgery is Feasible and Safe

BACKGROUND:

There is an increasing demand for surgery of degenerative spinal disease. Limited healthcare resources draw attention to the need for cost-effective treatments. Outpatient surgery, when safe and feasible, is more cost effective than inpatient surgery.

OBJECTIVE:

To study types and rates of complications after outpatient lumbar and cervical spine decompressions.

METHODS:

Complications were recorded prospectively in 1449 (1073 lumbar, 376 cervical) outpatients undergoing microsurgical decompression for degenerative spinal disease at the private Oslofjord Clinic from 2008 to 2013.

RESULTS:

Surgical mortality was 0%. A total of 51 (3.5%) minor and major complications were recorded in 51 patients. Three (0.2%) patients had to be admitted to a hospital the day of surgery. Twenty-two (1.5%) patients were admitted to a hospital within 3 months due to surgery-related events. The encountered complications were postoperative hematoma (0.6%), neurological deterioration (0.3%), deep wound infection (0.9%), dural lesions with cerebrospinal fluid leakage (1.0%), persistent dysphagia (0.1%), persistent hoarseness (0.1%), and severe pain/headache (0.4%). All of the life-threatening hematomas were detected within 6 and 3 hours after cervical and lumbar surgery, respectively.

CONCLUSION:

This series of 1449 consecutive outpatient microsurgical spine decompressions adds to the growing literature in favor of outpatient spinal surgery in properly selected patients. In our study, 99.8% of the patients were successfully discharged either to their homes or to a hotel on the day of surgery. The overall complication rate was 3.5%, surgical mortality was 0%, and only 1.5% had to be admitted to a hospital within 3 months after surgery.

Complications of the anterior approach to the cervical spine

OBJECTIVE: To evaluate the complications of anterior approach to the cervical spine in patients who underwent cervical arthrodesis with instrumentation. METHODS: Prospective and descriptive study was conducted from January 2009 to April 2010. All patients who underwent arthrodesis of the cervical spine by anterior approach were included, regardless the diagnosis. Access was made by the anterior approach on the right side. We evaluated the number of operated levels (1, 2 or 3 levels) and, the type of procedure performed: discectomy and placement of cage and plate (D+C+P), discectomy with placement of a cage (D+C) or corpectomy with placement of cage and plate (C+C+P). All complications related to surgical approach were reported. RESULTS: We studied 34 patients, 70% male. The average age was 50 years and mean follow-up was 8 months. Eighteen percent of patients had complications, distributed as follows: dysphasia (33%) and dysphonic (67%). Among patients who developed complications, most underwent to D+C+P (83%) and no complications were found in patients where no cervical plate was used. Regarding levels, both complications were identified in patients operated to one or two levels. However, in patients operated on three levels, only dysphonia was identified. CONCLUSION: The most frequent complication was dysphonia. Patients who presented more complications were those undergoing discectomy and fusion with cage and anterior cervical plate. All cases of dysphonia were in this group. The number of accessible levels does not seem to have affected the incidence of complications.

Vocal cord palsy after anterior cervical spine surgery: a qualitative systematic review

BACKGROUND CONTEXT

Vocal cord palsy (VCP) is a known complication of anterior cervical spine surgery. However, the true incidence and interventions to minimize this complication are not well studied.

PURPOSE

To conduct a systematic review to identify the incidence, risk, and interventions for VCP after anterior cervical spine surgery.

STUDY DESIGN

This is a qualitative systematic literature review.

SAMPLE

Prospective and retrospective trials of patients undergoing anterior cervical spine surgery that reported on postoperative VCP or recurrent laryngeal nerve palsy.

OUTCOME MEASURES

Primary: incidence of VCP after anterior cervical spine surgery; secondary: risk factors and interventions for prevention of VCP after anterior cervical spine surgery.

METHODS

Electronic searches were conducted on Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systemic Reviews for clinical studies reporting VCP in anterior cervical spine surgery, limited to studies published between 1995 and June 2013 in English and French languages. After selection of studies independently by two review authors, data on incidence, risk, and interventions were extracted. Qualitative analysis was performed on three domains: quality of studies, strength of evidence, and impact of interventions.

RESULTS

Our search has identified 187 abstracts, and 34 studies met our inclusion criteria. The incidence of VCP ranges from 2.3% to 24.2%. Significant heterogeneity in study design and definition of VCP were used in the published studies. There is good evidence that reoperation increases the risk of VCP. One study of moderate strength suggests that operating from the right side may increase the risk of VCP. Among the interventions studied, endotracheal tube (ETT) cuff pressure monitoring with deflation during retraction has shown to reduce the incidence from 6% to 2%, but this result was not confirmed by randomized control trials. Limited evidence exists for other interventions of intraoperative electromyographic monitoring and methylprednisolone.

CONCLUSIONS

Vocal cord palsy is a significant morbidity after anterior cervical surgery with incidence up to 24.2% in the immediate postoperative period, with a higher risk in reoperation of the anterior cervical spine. Moderate evidence exists for ETT cuff pressure adjustment in preventing this complication.

Neurological risks in scheduled spinal surgery

Spinal surgery is a high-risk specialty with an ever-increasing patient volume. Results are very largely favorable, but neurologic damage, the most severe complication, may leave major sequelae, some of which can be life-threatening. Neurologic complications may be classified according to onset (per- vs. postoperative) and surgical site (cervical vs. thoracolumbar). The present paper provides quantitative data for the risks involved. Knowledge of these complications and their risk of onset is the best means of guiding prevention strategies. The spine surgeon is part of a multidisciplinary team, with the radiologist and electrophysiologist, which is able to identify risk factors preoperatively and diagnose neurologic complications per- or postoperatively.

Long-term result of vocal cord paralysis after anterior cervical disectomy

PURPOSE

Anterior cervical disectomy and fusion (ACDF) is a highly effective and safe method for spinal cord and cervical root decompression. However, vocal cord paralysis (VCP) remains an important cause of postoperative morbidity. The true incidence and recovery course of postoperative VCP is still uncertain. This study is a report on VCP after ACDF to evaluate the incidence, recovery course, and possible risk factors.

METHODS

From 2004 to 2008, 1,895 consecutive patients underwent ACDF in our hospital and were followed up for at least 3 years. All surgeons were well trained and used a right-sided exposure. Prolonged VCP, where patients suffered from postoperative VCP lasting more than 3 months, was recorded and analyzed.

RESULTS

In this retrospective study, 9 of the 1,895 patients (0.47%) documented prolonged VCP lasting over 3 months. Six of the nine patients had total recovery within 9 months. Only three patients (0.16%) still had symptoms even after 3 years postoperatively. All symptoms of VCP, except hoarseness, could be improved. After matching with 36 non-VCP patients, no differences with regard to longer operative or anesthesia time, shorter neck, obesity, and prevertebral edema. All cases of prolonged course of postoperative VCP occurred in patients who underwent exposure at the C67 level.

CONCLUSION

In our study, only 0.47% documented prolonged postoperative VCP, while most patients recovered within 9 months. However, if symptoms last longer, there could be almost permanent VCP (0.16%). In our study, choking and dysphagia subsided mostly within 6 months, but hoarseness remained. The exposure of the C67 level obviously was a risk factor for postoperative VCP.

Maintaining endotracheal tube cuff pressure at 20 mm Hg to prevent dysphagia after anterior cervical spine surgery; protocol of a double-blind randomised controlled trial

BACKGROUND

In anterior cervical spine surgery a retractor is obligatory to approach the spine. Previous studies showed an increase of endotracheal tube cuff pressure after placement of a retractor. It is known that high endotracheal tube cuff pressure increases the incidence of postoperative dysphagia, hoarseness, and sore throat. However, until now no evidence supports the fact whether adjusting the endotracheal tube cuff pressure during anterior cervical spine surgery will prevent this comorbidity. We present the design of a randomized controlled trial to determine whether adjusting endotracheal tube cuff pressure after placement of a retractor during anterior cervical spine surgery will prevent postoperative dysphagia.

METHODS/DESIGN

177 patients (aged 18-90 years) scheduled for anterior cervical spine surgery on 1 or more levels will be included. After intubation, endotracheal tube cuff pressure is manually inflated to 20 mm Hg in all patients. Patients will be randomized into two groups. In the control group endotracheal tube cuff pressure is not adjusted after retractor placement. In the intervention group endotracheal tube cuff pressure after retractor placement is maintained at 20 mm Hg and air is withdrawn when cuff pressure exceeds 20 mm Hg. Endotracheal tube cuff pressure is measured after intubation, before and after placement and removal of the retractor. Again air is inflated if cuff pressure sets below 20 mmHg after removal of the retractor. The primary outcome measure is postoperative dysphagia. Other outcome measures are postoperative hoarseness, postoperative sore throat, degree of dysphagia, length of hospital stay, and pneumonia. The study is a single centre double blind randomized trial in which patients and research nurses will be kept blinded for the allocated treatment during the follow-up period of 2 months.

DISCUSSION

Postoperative dysphagia occurs frequently after anterior cervical spine surgery. This may be related to high endotracheal tube cuff pressure. Whether adaptation and maintaining the pressure after placement of the retractor will decrease the incidence of dysphagia, has to be determined by this trial.

TRIAL REGISTRATION

Netherlands Trial Register (NTR) 3542: http://www.trialregister.nl.

How to reduce recurrent laryngeal nerve palsy in anterior cervical spine surgery: a prospective observational study

BACKGROUND

Recurrent laryngeal nerve palsy (RLNP) occurs as a complication during anterior cervical spine surgery. In 2005 the authors demonstrated the high incidence of asymptomatic RLNP in a right-sided approach.

OBJECTIVE

This follow-up prospective observational study was designed to test 2 options said to reduce the rate of RLNP: reduced endotracheal cuff pressure and sinistral approach.

METHODS

Two hundred forty-two patients in whom anterior cervical spine surgery was performed were examined postoperatively with indirect laryngoscopy to evaluate the status of the vocal cords. All patients had a left-sided approach but 1 group (A, 149 patients) was operated on with an additional reduction of endotracheal cuff pressure to below 20 mm Hg. In 93 patients we could not reduce the cuff pressure. This group served as a control group (B). Both groups were compared with a historic control group with a right-sided approach and no cuff pressure reduction. In cases of vocal cord malfunction a follow-up examination was done 3 months later.

RESULTS

Group A (low cuff pressure) had a total rate of persisting symptomatic and asymptomatic RLNP of 1.3% and group B had a rate of 6.5% (normal cuff pressure). Compared with the historic study (N = 120) with a right-sided approach and a total rate of persisting RLNP of 13.3% in the left-sided approach, a marked reduction to 6.5% and 1.3% with an additional reduction of cuff pressure was seen.

CONCLUSION

The left-sided approach in anterior cervical spine surgery reduces the incidence of postoperative and permanent RLNP significantly. Endotracheal cuff pressure reduction used additionally decreases the rate of RLNP even more. These results indicate that anterior cervical spine surgery should be performed with a left-sided approach and, if possible, with an additional reduction of the endotracheal cuff pressure while the retractors are inserted.

Dysphagia, short-term outcomes, and cost of care after anterior cervical disc surgery

Dysphonia and dysphagia are common complications of anterior cervical discectomy (ACD). We sought to determine the relationship between dysphagia and in-hospital mortality, complications, speech therapy/dysphagia training, length of hospitalization, and costs associated with ACD. Discharge data from the Nationwide Inpatient Sample for 1,649,871 patients who underwent ACD of fewer than four vertebrae for benign acquired disease between 2001 and 2010 were analyzed using cross-tabulations and multivariate regression modeling. Dysphagia was reported in 32,922 cases (2.0 %). Speech therapy/dysphagia training was reported in less than 0.1 % of all cases and in only 0.2 % of patients with dysphagia. Dysphagia was significantly associated with age ≥65 years (OR = 1.5 [95 % CI 1.4-1.7], P < 0.001), advanced comorbidity (OR = 2.3 [2.0-2.6], P < 0.001), revision surgery (OR = 2.7 [2.3-3.1], P < 0.001), disc prosthesis placement (OR = 1.5 [1.0-2.0], P = 0.029), and vocal cord paralysis (OR = 11.6 [8.3-16.1], P < 0.001). Dysphagia was a significant predictor of aspiration pneumonia (OR = 8.6 [6.7-10.9], P < 0.001), tracheostomy (OR = 2.3 [1.6-3.3], P < 0.001), gastrostomy (OR = 30.9 [25.3-37.8], P < 0.001), and speech therapy/dysphagia training (OR = 32.0 [15.4-66.4], P < 0.001). Aspiration pneumonia was significantly associated with in-hospital mortality (OR = 15.9 [11.0-23.1], P < 0.001). Dysphagia, vocal cord paralysis, and aspiration pneumonia were significant predictors of increased length of hospitalization and hospital-related costs, with aspiration pneumonia having the single largest impact on length of hospitalization and costs. Dysphagia is significantly associated with increased morbidity, length of hospitalization, and hospital-related costs in ACD patients. Despite the known risk of dysphagia in ACD patients and an established role for the speech-language pathologist in dysphagia management, speech-language pathology intervention appears underutilized in this population.

Incidence and risk factors of the retropharyngeal carotid artery on cervical magnetic resonance imaging

STUDY DESIGN

Retrospective cohort.

OBJECTIVE

Define incidence of anomalous carotid vasculature and associated risk factors as pertains to the anterior approach.

SUMMARY OF BACKGROUND DATA

The carotid artery system, including the common, internal, and external branches, is lateral to the foramen transversarium. If unrecognized, aberrancies in carotid vessel anatomy can lead to devastating complications.

METHODS

A total of 1000 cervical magnetic resonance imagings were screened to localize the carotid artery respective to medial/lateral location of the vessel at each segment from C2-C3 to C6-C7 bilaterally. Vessel location was classified in 3 zones: lateral to the vertebral foramen (type I) (normal); between the lateral foramen and uncoverterbral joint (type II); and medial to the uncovertebral joint (type III). Type III locations were compared with age-matched controls for assessment of cervical alignment via the Ishihara index, C2-C7 angle, and degree of spondylosis.

RESULTS

A total of 123 patients demonstrated carotid artery anomalies (type II and III) (12.3%). Twenty-six patients had type III aberrancy (2.6%). Patients with anomalies were significantly older and more likely to be female (60 vs. 51 yr of age, 74% vs. 57% female, respectively, P < 0.05). The type III group average age was 66.1 years and 88% were female. Aberrancies were more likely right-sided and at C3-C4 or cranial. C2-C7 angle showed significantly greater kyphosis in patients with anomalies compared with controls (6.2 vs. 14.4, P = 0.03). The number of severely spondolytic segments was significantly greater in patients with Type III locations than controls (2.0 vs. 1.1 P < 0.05).

CONCLUSION

Carotid arterial anomalies occurred in 12.3% of cases; severe aberrancy was present in 2.6% of patients. In elderly females with kyphotic alignment, a high index of suspicion must be raised for aberrancy. Preoperative assessment of the vasculature in the anterior neck may avoid catastrophic complications.

Clinically relevant anatomy of recurrent laryngeal nerve

STUDY DESIGN

An anatomic study of anterior cervical dissection of 11 embalmed cadavers.

OBJECTIVE

To determine the anatomic relationship of the recurrent laryngeal nerve (RLN) to the cervical spine and demonstrate vulnerability of the nerve during anterior surgical approach.

SUMMARY OF BACKGROUND DATA

The most common complications of anterior neck surgery are dysphagia and RLN palsy. The morbidity of these complications has led to the investigation of the impact of sidedness in anterior cervical spine surgery.

METHODS

Eleven adult cadavers (5 male/6 female) were dissected bilaterally to expose the path of the recurrent laryngeal nerve.

RESULTS

The right RLN branched from the vagus nerve at the level of T1-T2 or inferior in all specimens. After looping around the subclavian artery, the right RLN became invested in the tracheoesophageal fascia greater than 0.5 cm inferior to C7-T1 in all specimens. The RLN traveled superiorly, slightly anterior to the tracheoesophageal groove, before coursing between the trachea and the thyroid. In 82% (9 of 11) of right-sided dissections, the RLN entered the larynx at or inferior to C6-C7. After looping around the aortic arch, the left RLN was invested in the tracheoesophageal fascia inferior to the T2 level in 100% (10 of 10) of cadavers. The nerve traveled slightly anterior to the tracheoesophageal groove and within the tracheoesophageal fascia before coursing between the trachea and thyroid. In all the left-sided dissections, the RLN entered the larynx at or inferior to C6-C7.

CONCLUSION

This study found that superior to C7-T1, both RLNs had similar anatomic courses and received similar protection via surrounding soft-tissue structures. From an anatomic perspective, the authors did not appreciate a side-to-side difference superior to this level that could place either nerve under greater risk for injury.

Anterior approach for complex cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is a slowly progressive disease resulting from age-related degenerative changes in the spine that can lead to spinal cord dysfunction and significant functional disability. The degenerative changes and abnormal motion lead to vertebral body subluxation, osteophyte formation, ligamentum flavum hypertrophy, and spinal canal narrowing. Repetitive movement during normal cervical motion may result in microtrauma to the spinal cord. Disease extent and location dictate the choice of surgical approach. Anterior spinal decompression and instrumented fusion is successful in preventing CSM progression and has been shown to result in functional improvement in most patients.

An aid to the explanation of surgical risks and complications: the International Spinal Surgery Information Sheet

STUDY DESIGN

Presentation and analysis of a patient information sheet.

OBJECTIVE

To produce an evidence-based information sheet that will serve as an aide-memoire to the process of taking informed consent prior to spinal surgery.

SUMMARY OF BACKGROUND DATA

Consent for a surgical intervention is the end of a process of discussion between the surgeon and the patient. It is essential that the patient has been provided with sufficient information to make an informed judgment as to whether the benefits of a proposed procedure will outweigh its risks.

METHODS

We searched MEDLINE, the Cochrane database of systematic reviews and personal libraries for articles reporting complications of the surgical treatment of spinal diseases with particular reference to the most commonly treated conditions. A draft document was drawn up referencing the odds of specific complications. This was circulated to the National Health Service Scotland Central Legal Office for scrutiny and to an English language expert at the University of Edinburgh for translation to lay English. Finally, the document was issued to 50 patients in the outpatient clinic and scored on visual analog scales (VAS) for the ease of understanding, usefulness, and length.

RESULTS

The product of this project was a two-page A4 sheet, with the front page outlining information applicable to spinal surgery "in general" and a back page detailing all common risks, relating to a headline procedure, that a Court of Law would expect a surgeon to discuss. The patients' VAS score (0-10) for "ease of understanding" was 8.8 ± 1.3 and for "usefulness" 8.9 ± 1.0 (means ± SD). Forty-three of 50 patients (86%) indicated that the length of the document was "just right" and seven (14%) of them that it was "too long."

CONCLUSION

The ISSiS is user friendly and can be employed as a tool in the process of obtaining consent.

Dysphagia after anterior cervical spine surgery: incidence and risk factors

OBJECTIVE

To evaluate risk factors for the development of dysphagia after anterior cervical surgery.

METHODS

The records of 249 patients who underwent anterior cervical surgery were reviewed. The presence and severity of dysphagia were assessed with the Dysphagia Disability Index 6 weeks and 3, 6, and 12 months after surgery. Age; sex; ethnicity; cigarette smoking; previous cervical surgeries; reoperation for same pathology; type of procedure, incision, and instrumentation; number and levels involved; side of procedure, length of surgery; and use of postoperative bracing were analyzed.

RESULTS

During the first 6 months after surgery, 27 (10.8%) patients developed dysphagia. From these patients the presence of dysphagia at 6 weeks and at 3 and 6 months was 88.8%, 29.6%, and 7.4%, respectively. By 12 months, dysphagia had resolved in all cases. The mean age of patients with dysphagia was 55 years (SD 12.98) and 50 years (SD 12.07) in patients without dysphagia (P = 0.05). Dysphagic patients had an average of 2.2 (SD 1.15) levels operated compared with 1.84 (SD 0.950) in nondysphagic patients (P = 0.05). Patients who developed dysphagia were most often treated at C4-5 (67%) and C5-6 (81%: P < 0.001). Although mean operative time was slightly longer in patients with dysphagia (186 minutes) compared with those without (169 minutes), the difference was not significant.

CONCLUSIONS

In our patients, the incidence of dysphagia was low, and it had completely resolved at 12 months in all cases. Risk factors for dysphagia were multilevel procedures, involvement of C4-5 and C5-6, and age.

Variations in the course of the cervical vagus nerve on thyroid ultrasonography

BACKGROUND AND PURPOSE

Only 1 ultrasonography study that described the variation of the VN had been published at the time our research was begun. The purpose of this study was to evaluate the incidence and type of variation in the course of the cervical VN on thyroid ultrasonography.

MATERIALS AND METHODS

From August 2009 to September 2010, 163 consecutive patients were evaluated by sonography for the screening and characterization of thyroid nodules (mean age, 49.0 ± 14.4 years, male:female, 20:143). Two types of variation were defined as follows: 1) anterior variation, when the course of the VNs changed from the typical location to an anterior location in front of the CCA; and 2) medial variation, when the course of the VNs changed from the typical location to a location medial to the CCA (between CCA and thyroid gland). The incidence of the each variation was studied.

RESULTS

Variation in the course of the VN occurred in 5.5% (18/326) of cases. The anterior variation was observed in 4.3% (14/326, right:left = 4:10), and the medial variation was observed in 1.2% (4/326, right:left = 3:1). For both variations, the VN was close to or nearly abutted the thyroid gland after it changed course.

CONCLUSIONS

Variation in the course of the cervical VN could be assessed by ultrasonography. Two variations were observed in 5.5% of cases. The anterior variation was more common than the medial variation.

Feasibility of anterior cervical discectomy and fusion as an outpatient procedure

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) procedures are increasingly being managed on an outpatient basis. Currently there are no definitive guidelines within the literature that delineate which patient population can safely be managed as such. The purpose of this study is to demonstrate that ACDF procedures, within a selective patient population at our institution, can be safely performed on an outpatient basis.

METHODS

This is a retrospective chart review within one physician's practice of patients undergoing instrumented ACDF procedures using allograft. This sample included 117 patients who underwent one- and two-level ACDF procedures from November 2005 to April 2009. Hospital length of stay and hospital readmissions were noted. Complication rates in the outpatient population were assessed to determine the feasibility of outpatient management for selective patients undergoing ACDF procedures.

RESULTS

A total of 59 patients (50%) were treated on an outpatient basis. Sixty-eight patients underwent single level ACDF procedures, 38 patients (56%) of which were discharged on the same day. Forty-nine patients underwent two-level ACDF procedures, 21 patients (43%) of which were discharged on the same day. There was one complication (1.4%) in patients who were discharged on the same day. That patient required readmission for 23-hour observation secondary to neck swelling.

CONCLUSIONS

ACDF procedures involving single and two-level fusions can safely be performed on an outpatient basis. Complication rates associated with this procedure are low, with critical postoperative complications involving respiratory compromise occurring very infrequently and in the immediate postoperative period.

Análise de fatores associados à lesão do nervo laríngeo recorrente em cirurgias de discectomia cervical via anterior

OBJETIVO: Estudar os possíveis fatores associados com lesão do NLR após cirurgia de hérnia discal cervical com abordagem anterior. MÉTODOS: No período de junho/2009 a junho/2010, avaliamos 30 pacientes submetidos a tratamento cirúrgico de hérnia discal via anterior no Hospital São Lucas da PUC-RS. No pré-operatório, foi realizada a medida da circunferência cervical (ao nível da cartilagem cricóide) e da altura cervical (do ângulo da mandíbula à borda superior da clavícula). No perioperatório, avaliamos o tempo e a dificuldade de entubação, o tempo cirúrgico, o lado da abordagem, o número de níveis operados, bem como o tipo de incisão (transversa/longitudinal) e o uso de halo craniano. Realizou-se uma avaliação videoendoscópica da laringe (VEL), em busca de lesão do NLR, no pré-operatório e no décimo dia após a cirurgia. Pacientes que apresentaram resultado anormal na VEL foram considerados com lesão do NLR e submetidos à reavaliação mensal até a recuperação espontânea ou no período máximo de seis meses quando a lesão foi considerada definitiva. RESULTADOS: Encontramos 3/30 (10%) casos de lesões não definitivas do NLR que se recuperaram em até 120 dias pós-operatórios. Os pacientes com lesão do NLR apresentaram uma maior circunferência do pescoço, tempo cirúrgico e número de níveis operados em relação aos pacientes sem lesão do NLR. Também, pacientes com lesão do NLR apresentaram um menor comprimento do pescoço. Duas lesões ocorreram na abordagem pelo lado direito e uma pelo lado esquerdo. Todos os pacientes com lesão tiveram incisão transversa e não fizeram uso de halo craniano. CONCLUSÃO: A abordagem pelo lado direito apresentou maior índice de complicações com o NLR. Apesar de o número limitado de pacientes não permitir conclusões estatisticamente significativas, fatores anatômicos intrínsecos do paciente como pescoço curto e diâmetro do pescoço aumentado, bem como tempo cirúrgico, e dificuldades técnicas que possam aumentar o tempo cirúrgico podem estar associados com lesão do NLR. Novos estudos avaliando as variáveis acima estudadas devem ser considerados.

Papel da videoendoscopia da laringe no diagnóstico de lesão do nervo laríngeo recorrente na abordagem cervical anterior

INTRODUÇÃO: o reconhecimento da lesão do nervo laríngeo recorrente (NLR) após tratamento cirúrgico de hérnia discal cervical via anterior é importante na evolução clínica do paciente e, em especial, nos casos de reintervenção. O real papel da videoendoscopia da laringe (VEL) de rotina no pós-operatório não tem sido completamente estudado. OBJETIVO: identificar a prevalência de lesões do NLR em pacientes sintomáticos ou não através da VEL após cirurgia de hérnia cervical via anterior. MÉTODOS: no período de Junho de 2009 a Julho de 2010 selecionamos 30 pacientes submetidos a tratamento cirúrgico de hérnia discal no Hospital São Lucas da PUC-RS. Realizou-se avaliação por VEL no pré-operatório e no décimo dia após a cirurgia. Pacientes que apresentaram um resultado anormal da VEL foram considerados com lesão do NLR e foram reavaliados mensalmente até a recuperação espontânea, ou no período máximo de seis meses, quando a lesão foi considerada definitiva. RESULTADOS: encontramos evidência de lesão do NLR em 3/30 (10%) dos pacientes, sendo que todos se apresentavam assintomáticos no momento do exame. Dentre as lesões, 2/30 (66,6%) ocorreram após abordagem cirúrgica pelo lado direito e 1/30 (33,3%) pelo lado esquerdo. Não encontramos nenhuma lesão definitiva, sendo o período máximo de recuperação de 120 dias. CONCLUSÃO: a avaliação por VEL no período pós-operatório pode ser útil para diagnosticar lesões do NLR, principalmente em pacientes assintomáticos. A falta de suspeita clínica não exclui a possibilidade de lesão do LNR.

[Persistent dysphagia and mechanical glottic paralysis. Complications of a ventral fracture spondylodesis with Forestier's disease]

Persistent dysphagia after ventral instrumentation of a patient with a cervical spine fracture and diffuse idiopathic skeletal hyperostosis (DISH, or Forestier's disease) is a rare but dramatic complication. In this case report some pathogenetic factors are discussed. Accurate resection of the spondylophytes should be considered to avoid a ventral protrusion of the plate.

Preoperative functional assessment of the recurrent laryngeal nerve in patients with cervical vertebra fracture: case report

OBJECTIVE

Injury to the recurrent laryngeal nerve may occur during surgical intervention to the anterior part of the neck. However, some disorders can lead to damage to the recurrent laryngeal nerve before surgery. We report 2 cases of lower cervical vertebra fracture, leading to 1-sided injury of the recurrent laryngeal nerve.

CLINICAL PRESENTATION

One man and 1 woman with neck injuries were admitted to our hospital. The man had a C7-T1 dislocation fracture, and the woman had a C6-C7 dislocation fracture. Both patients had similar fractures and similar clinical presentations. The distinctive feature of these cases is that both patients had dysphonia after the initial injuries but before surgery.

INTERVENTION

Both patients were treated surgically, and anterior and posterior cervical stabilization was performed. During surgical intervention to the anterior part of the neck for cervical fixation, the injured side (where the vocal cords did not move during an indirect laryngoscopy) was preferred.

CONCLUSION

Patients with a cervical vertebra fracture with dysphonia and hoarseness should be examined for vocal cord dysfunction. Surgical intervention should be performed on the side of the injured recurrent laryngeal nerve.